Apparatus for processing plastic material

Abstract

The invention relates to an apparatus for the pretreatment and subsequent conveying or plastification of plastics, with a container with a mixing and/or comminution implement that is rotatable around an axis of rotation, wherein, in a side wall, an aperture is formed, through which the plastics material can be removed, a conveyor being provided, with a screw rotating in a housing, wherein the imaginary continuation of the longitudinal axis of the conveyor in a direction opposite to the direction of conveying passes the axis of rotation, where, on the outflow side, there is an offset distance between the longitudinal axis and the radius that is parallel to the longitudinal axis, and in that screw rotates clockwise, when seen from the starting point of the screw in the direction towards the end or towards the discharge aperture of the conveyor.

1 . An apparatus for the pretreatment of plastics, in particular of thermoplastics waste for recycling purposes, with a container ( 1 ) for the material to be processed, where the arrangement has, in the container ( 1 ), at least one mixing and/or comminution implement ( 3 ) which rotates around an axis ( 10 ) of rotation and which is intended for the mixing, heating and optionally comminution of the plastics material,
 where an aperture ( 8 ) through which the pretreated plastics material can be removed from the interior of the container ( 1 ) is formed in a side wall ( 9 ) of the container ( 1 ) in the region of the level of the, or of the lowest, mixing and/or comminution implement ( 3 ) that is closest to the base,   where at least one conveyor ( 5 ), in particular one extruder ( 5 ), is provided to receive the pretreated material, and has at least one screw ( 6 ) which rotates in a housing ( 16 ) and which in particular has plastifying or agglomerating action, where the housing ( 16 ) has, located at its end ( 7 ) or in its jacket wall, an intake aperture ( 80 ) for the material to be received by the screw ( 6 ), and there is a connection between the intake aperture ( 80 ) and the aperture ( 8 ),   wherein   the imaginary continuation of the central longitudinal axis ( 15 ) of the conveyor ( 5 ) or of the screw ( 6 ) closest to the intake aperture ( 80 ), in a direction opposite to the direction ( 17 ) of conveying of the conveyor ( 5 ), passes, and does not intersect, the axis ( 10 ) of rotation, where, on the outflow side or in the direction ( 12 ) of rotation or of movement of the mixing and/or comminution implement ( 3 ), there is an offset distance ( 18 ) between the longitudinal axis ( 15 ) of the conveyor ( 5 ) or of the screw ( 6 ) closest to the intake aperture ( 80 ), and the radius ( 11 ) of the container ( 1 ) and that is parallel to the longitudinal axis ( 15 ) and that proceeds outwards from the axis ( 10 ) of rotation of the mixing and/or comminution implement ( 3 ) in the direction ( 17 ) of conveying of the conveyor ( 5 ),   and wherein the screw ( 6 ), or the screw ( 6 ) closest to the intake aperture ( 80 ), rotates clockwise when viewed from the starting point, generally close to the container and to the intake, of the screw ( 6 ), or from the intake aperture ( 80 ), in the direction towards the end or to the discharge aperture of the conveyor ( 5 ).   
     
     
         2 . The apparatus according to  claim 1 , wherein in the upper region, and optionally also in the lower region, of the intake aperture ( 80 ) a wedge-shaped intake geometry is formed. 
     
     
         3 . The apparatus according to  claim 1 , wherein in the lower region of the intake aperture ( 80 ) there is a conveying device, for example in the form of a displaceable intake element or of a displaceable barrier, having a stripping action in the direction ( 17 ) of conveying of the screw ( 6 ). 
     
     
         4 . The apparatus according to  claim 1 , wherein, for a conveyor ( 5 ) in contact with the container ( 1 ), the scalar product of the direction vector that is associated with the direction ( 19 ) of rotation and that is tangential to the circle described by the radially outermost point of the mixing and/or comminution implement ( 3 ) or that is tangential to the plastics material transported past the aperture ( 8 ) and that is normal to a radius ( 11 ) of the container ( 1 ), and that points in the direction ( 12 ) of rotation or of movement of the mixing and/or comminution implement ( 3 ) and of the direction vector ( 17 ) that is associated with the direction of conveying of the conveyor ( 5 ) at each individual point or in the entire region of the aperture ( 8 ) or immediately radially in front of the aperture ( 8 ) is zero or negative. 
     
     
         5 . The apparatus according to  claim 1 , wherein the angle (α) included between the direction vector that is associated with the direction ( 19 ) of rotation of the radially outermost point of the mixing and/or comminution implement ( 3 ) and the direction vector ( 17 ) that is associated with the direction of conveying of the conveyor ( 5 ) is greater than or equal to 90° and smaller than or equal to 180°, measured at the point of intersection of the two direction vectors ( 17 ,  19 ) at the inflow-side edge that is associated with the aperture ( 8 ) and that is situated upstream in relation to the direction ( 12 ) of rotation or of movement of the mixing and/or comminution implement ( 3 ), in particular at the point ( 20 ) that is on the said edge or on the aperture ( 8 ) and is situated furthest upstream. 
     
     
         6 . The apparatus according to  claim 1 , wherein the angle (β) included between the direction vector ( 19 ) that is associated with the direction ( 12 ) of rotation or of movement and the direction vector ( 17 ) that is associated with the direction of conveying of the conveyor ( 5 ) is from 170° to 180°, measured at the point of intersection of the two direction vectors ( 17 ,  19 ) in the middle of the aperture ( 8 ). 
     
     
         7 . The apparatus according to  claim 1 , wherein the distance ( 18 ) is greater than or equal to half of the internal diameter of the housing ( 16 ) of the conveyor ( 5 ) or of the screw ( 6 ), and/or greater than or equal to 7%, preferably greater than or equal to 20%, of the radius of the container ( 1 ), or wherein the distance ( 18 ) is greater than or equal to the radius of the container ( 1 ). 
     
     
         8 . The apparatus according to  claim 1 , wherein the imaginary continuation of the longitudinal axis ( 15 ) of the conveyor ( 5 ) in a direction opposite to the direction of conveying is arranged in the manner of a secant in relation to the cross section of the container ( 1 ), and, at least in sections, passes through the space within the container ( 1 ). 
     
     
         9 . The apparatus according to  claim 1 , wherein the conveyor ( 5 ) is attached tangentially to the container ( 1 ) or runs tangentially in relation to the cross section of the container ( 1 ), or wherein the longitudinal axis ( 15 ) of the conveyor ( 5 ) or of the screw ( 6 ) or the longitudinal axis of the screw ( 6 ) closest to the intake aperture ( 80 ) runs tangentially with respect to the inner side of the side wall ( 9 ) of the container ( 1 ), or the inner wall of the housing ( 16 ) does so, or the envelope of the screw ( 6 ) does so, where preferably there is a drive connected to the end ( 7 ) of the screw ( 6 ), and that the screw provides conveying, at its opposite end, to a discharge aperture which is in particular an extruder head and which is arranged at the end of the housing ( 16 ). 
     
     
         10 . The apparatus according to  claim 1 , wherein there is immediate and direct connection between the aperture ( 8 ) and the intake aperture ( 80 ), without substantial separation, in particular without a transfer section or conveying screw. 
     
     
         11 . The apparatus according to  claim 1 , wherein the mixing and/or comminution implement ( 3 ) comprises implements and/or blades ( 14 ) which, in the direction ( 12 ) of rotation or of movement, have a comminuting, cutting and heating effect on the plastics material, where the implements and/or blades ( 14 ) are preferably arranged or formed on or at a rotatable implement carrier ( 13 ) which is in particular a carrier disc ( 13 ) and which is in particular arranged parallel to the basal surface ( 12 ). 
     
     
         12 . The apparatus according to  claim 1 , wherein the manner of formation, set-up, curvature and/or arrangement of the frontal regions or frontal edges ( 22 ) that are associated with the mixing and/or comminution implements ( 3 ) or with the blades ( 14 ), act on the plastics material and point in the direction ( 12 ) of rotation or of movement, differs when comparison is made with the regions that, in the direction ( 12 ) of rotation or of movement, are at the rear or behind. 
     
     
         13 . The apparatus according to  claim 1 , wherein the container ( 1 ) is in essence cylindrical with circular cross section and with a level basal surface ( 2 ) and with, orientated vertically in relation thereto, a side wall ( 9 ) which has the shape of the jacket of a cylinder, and/or the axis ( 10 ) of rotation of the mixing and/or comminution implements ( 3 ) coincides with the central axis of the container ( 1 ), and/or the axis ( 12 ) of rotation or the central axis are orientated vertically and/or normally in relation to the basal surface ( 2 ). 
     
     
         14 . The apparatus according to  claim 1 , wherein the lowest implement carrier ( 13 ) or the lowest of the mixing and/or comminution implements ( 3 ) and/or the aperture ( 8 ) are arranged close to the base at a small distance from the basal surface ( 2 ), in particular in the region of the lowest quarter of the height of the container ( 1 ), preferably at a distance of from 10 mm to 400 mm from the basal surface ( 2 ). 
     
     
         15 . The apparatus according to  claim 1 , wherein the conveyor ( 5 ) is a single-screw extruder ( 6 ) with a single compression screw ( 6 ), or is a twin- or multiscrew extruder, where the diameters d of the individual screws ( 6 ) are all identical.